Sunday, April 20, 2025

C Programming Viva Questions Data Types

Viva Questions based on C Programming Data Types

 

1. What are data types in C?

Answer: It defines the type of data that we can store in a variable. They tell the compiler how much space to allocate and how to interpret the value.

 

2. What are the different types of data types in C?

Answer: C has three primary data types:

•   Basic data types: int, float, char, double

•   Derived data types: array, pointer, structure, union

•   Enumeration and void types: enum, void

 

3. What is the size of int, float, double, and char in C?

Answer: Sizes may vary by system, but typically:

•   int: 4 bytes

•   float: 4 bytes

•   double: 8 bytes

•   char: 1 byte

 

4. What is the difference between float and double?

Answer:

•   float is a single-precision (32-bit) floating point.

•   double is a double-precision (64-bit) floating point. double is more accurate and can store larger values.

 

5. What is the use of the void data type?

Answer: void means “no type.” It is used:

•   In functions that return nothing: void functionName()

•   For generic pointers: void *ptr

 

6. What is the difference between signed and unsigned data types?

Answer:

•   Signed data types can store both positive and negative values.

•   Unsigned data types can only store positive values, which allows a larger positive range.

Example:

signed int ranges from2,147,483,648 to 2,147,483,647

unsigned int ranges from 0 to 4,294,967,295

 

7. What is the use of sizeof operator?

Answer: The sizeof operator returns the size (in bytes) of a data type or variable.

Example: sizeof(int) gives 4 on most systems.

 

8. What are type modifiers in C?

Answer: Type modifiers are keywords that alter the meaning of the base data types.

They are: signed, unsigned, long, and short.

Example: unsigned long int increases the range for positive integers.

 

9. Can we use char for storing small integers?

Answer: Yes. A char is 1 byte, so it can store small integer values (typically –128 to 127 for signed char).

 

10. What happens if we assign a float value to an int variable?

Answer: The decimal part is truncated, not rounded.

Example:

float x = 5.9;

int y = x; // y becomes 5